I Took the Viral Video of Justin Bieber Serenading Selena Gomez

WEST HOLLYWOOD, CA - FEBRUARY 27: Actress Selena Gomez and singer Justin Bieber arrive at the Vanity Fair Oscar party hosted by Graydon Carter held at Sunset Tower on February 27, 2011 in West Hollywood, California. (Photo by George Pimentel/WireImage)WireImage

Imagine you're in Los Angeles on vacation, staying with your best friend. You want a chill night, so you head to your favorite sushi spot. It's tiny, and you're tired, so you wear your jeans and Chucks. You're not out to impress anyone (except maybe by the sheer amount of sushi you're about to throw back).

But the wait's over an hour, so you go across the street to a laidback hotel to kill time and down a few appetizers. You're talking with your friends and telling stories. And then Justin Bieber walks in.

That was Lindsey Cavanaugh's reality last Friday night. "Of course, the night this happens, I’m dressed like school teacher," the Boulder-based photographer starts her story with a laugh. "There were probably 15 people in there. The guy said we could sit anywhere want, so we take the couches. All the sudden, my friend looks at me like a deer in the headlights. She’s staring at me, and I can't figure out why she's being so weird. And then I realize she's whispering 'Justin. Bieber.' under her breath."

"As soon as I saw his neck tattoo, I knew it was him," she continues. "We were trying to keep it cool but it was difficult to speak about anything. Then an older gentleman came over to talk to him, and was asking him what kind of music he wanted to hear on the piano. It sounded like he was maybe going to play, but we were like, 'There's no way.' And then sure enough. They hooked up a microphone. He sits down and immediately begins beautifully playing on the piano. He plays a few notes of 'Sorry' and then starts belting it out." There's always live music in the lobby of the Montage Hotel; usually the world's most famous (and occasionally infamous) pop star is not the one making it.

And then things got even weirder. After he played around on the piano for a bit, Justin, who appeared to be alone, came and sat down next to Lindsey and her friends — though not before politely asking if her could join them. He jumped in on their conversation, asking what they were up to, where they were from, and what they were doing later that night.

They asked him if he'd planned to play music at the hotel that night, and he insisted it was spur of the moment. "I love music, and when I get a chance, I do it." He continued hanging out with them, and then one of Lindsey's friends casually asked — or as casually as you can ask Justin Bieber anything — what he was doing that night. "I’m meeting up with my ex-girlfriend," he said.

They didn't ask questions, nor did their brains explode, but that's mostly because they didn't have time. Justin popped outside, and then returned shortly with his previously-mentioned ex-girlfriend who is, sure enough, Selena Gomez. The two sat on a couch for a few minutes catching up, and then one thing led to another, and all of a sudden they were slow-dancing as the hotel's main piano man (who, it goes without saying, is not a pop star) sang "Easy" by the Commodores. He dipped her backwards. She laughed. Lindsey and her friends tried in vain not to stare.

"All of a sudden, Justin hijacked the microphone again and started serenading Selena with a flawless rendition of the Temptations classic, 'My Girl.' "We didn't want to take pictures during their slow dance, because it was such a private thing. But within five seconds, he stands up. And we were like, okay, you’re inviting us into this moment." Lindsey got much of the performance on camera, posted it to Instagram, and then her phone promptly died.

The girls eventually said their goodbyes to Justin — by this time, the sushi restaurant had been blowing up the girls' phones to alert them that their table was ready, like, an hour ago. But first, they asked for a picture with him, because you can't endure a moment like this and not. But since the hotel was so empty, they couldn't find anyone to take the photo, so Justin called Selena over, who sweetly snapped a few shots.

"The funny thing is," Lindsey says, "I posted the videos, and then my phone’s not on for two hours. I turn it back on, and my Instagram was seizing. I’ve never experienced anything like this. I couldn’t even click on anything." She's gained 10,000 new Instagram followers — and a whole new appreciation for the singer. "It was such a crazy thing, but I also feel like I got to see an incredible concert. He's so talented. You can really tell he loves music. Duh of the century."